There are instances of erectile impotence in which the patient does not respond to more conventional therapy and the surgical implanting of a penile prosthesis may be the only practical means of remedying the impotency.
Several types of penile prostheses have been employed in the past. One type of penile prosthesis is a pair of rods of suitable stiffness which are surgically implanted into the corpus cavernosum of the penis. One disadvantage of some of the rod-type implants is the permanent stiffness of the rod which can be a source of physical pain and/or embarrassment to the patient. The prostheses disclosed in U.S. Pat. No. 3,893,476 and U.S. Pat. No. 4,066,073 are representatives of the rod type prostheses.
Another type of penile prosthesis which is available is the inflatable prosthesis of U.S. Pat. No. 3,954,102. The patented prosthesis includes two fairly long inflatable and distensible tubes that are surgically implanted in the corpus cavernosum of the penis. Each of the two tubes is connected by tubing to a manually operable pressure bulb for inflating fluid, which is implanted in the scrotal sac, and a reservoir which is placed in the abdominal cavity. The operation required to implant the prosthesis is relatively complex and lengthy.
Recently, penile prostheses have been patented and made commercially available which are essentially cylinders which contain a hydraulic system comprising a pressure chamber, a reservoir and a manually operable pump for transferring fluid from the reservoir to the pressure chamber. The operation for placing the cylinders in the corpora cavernosa is relatively simple and quick. Representative of such implants are those of U.S. Pat. Nos. 4,353,360, 4,267,829 and 4,383,525.
Still more recently, a penile prosthesis has been made commercially available that comprises two implants containing pressure chambers that are implanted in the corpora, a manually operable pump that is implanted in the scrotal sac and connecting tubing. This type of prosthesis is relatively less expensive than the self-contained cylinders. The surgical procedure for implanting this type of prosthesis is relatively simple and does not require abdominal surgery. Representative of this prosthesis is the prosthesis of U.S. Pat. No. 4,726,360 and others.
Although the previously patented prostheses are useful and valuable devices, it would be desirable to have an improved penile prosthesis which does not require manual pumping to achieve an erection. A number of designs for such prosthesis have been proposed and patented but none have become commercially available.